Use of cellular mobile devices for accessing computer data networks has recently increased dramatically. These mobile devices, often referred to as “smart” phones, provide a platform for both cellular phone calls and cellular-based access to computer data services. For example, a typical cellular network is a collection of cells that each include base stations capable of transmitting and relaying radio signals to subscribers' mobile devices. A “cell” generally denotes a distinct area of a cellular network that utilizes a particular frequency or range of frequencies for transmission of data. A typical base station is a tower to which are affixed a number of antennas that transmit and receive the data over the particular frequency. Mobile devices may transmit radio signals at the designated frequency to the base stations to initiate cellular telephone calls or packet-based data services.
With respect to data services, cellular service providers convert the cellular signals, e.g., Time Division Multiple Access (TDMA) signals, Orthogonal Frequency-Division Multiplexing (OFDM) signals or Code Division Multiple Access (CDMA) signals, received from mobile devices at the base stations into Internet protocol (IP) packets for transmission within packet-based networks. A number of standards have been proposed to facilitate this conversion and transmission of cellular signals to IP packets, such as a general packet radio service (GPRS) standardized by the Global System for Mobile Communications (GSM) Association, a Universal Mobile Telecommunications System (UMTS), an evolution of UMTS referred to as Long Term Evolution (LTE), as well as other standards proposed by the 3rd Generation Partnership Project (3GPP), 3rd Generation Partnership Project 2 (3GGP/2) and the Worldwide Interoperability for Microwave Access (WiMAX) forum.
In this way, the cellular service provider provides data services and connectivity to the cellular mobile devices, allowing the cellular mobile devices to access various packet data networks (PDNs). The PDNs provide a variety of packet-based data services to the cellular mobile device and allow the wireless devices to exchange service data with application or other servers of the PDNs. PDNs may include, for example, the Internet, an enterprise intranet, a layer three (L3) VPN, and a service provider's private network. A service provider's cellular network transports subscriber traffic exchanged between the cellular mobile device and the PDN.
The ubiquitous use of cellular mobile devices and the ever increasing desire by users for fast network access from around the world has presented many challenges. For example, the use of cellular mobile devices have placed a high demand for data services over the service provider's cellular network, often straining the cellular network and resulting in delayed or lost data communications. Some cellular mobile devices, in addition to supporting connections to a PDN via a radio interface, also support wireless capabilities to exchange data via an alternate access network that is separate from the cellular network of the mobile service provider. For example, many cellular mobile devices include a wireless local area network (WLAN) interface that provides data service when in the presences of a WiFi “hotspot” or other wireless access point (WAP). Other examples of such wireless capabilities may include Bluetooth or Near Field Communication (NFC). When in the presence of a WLAN, a user may wish to transition the data services of the cellular mobile device to the WLAN so as to accelerate data transmissions and avoid any delays associated with the cellular network.